Access to Metal‐Bridged Osmathiazine Derivatives by a Formal [4+2] Cyclization

Abstract

Treatmento fo smacyclopentadiene derivatives 1 with phenyl or isopropyl isothiocyanate gave the fused five and six-membered osmacycles 2-5 by aformal [4+ +2] cyclization. The facile protonation of the newly generated exocyclic imine in complexes 2-5 afforded conjugation-extended osmacycle derivatives 6-9.C ompounds 2-9 each contain two main-group heteroatoms (N and S) in the fused six-membered ring located at the ortho (for S) and para (for N) positions relative to the osmiumc entre;t hese speciesc an be re-garded as rare osma-1,3-thiazine derivatives and represent the first fused metallathiazine derivatives. In contrast to the non-planar organic 6H-1,3-thiazine, nearly coplanar metallathiazines 8 and 9 can be achievedb yt uning the groups on the two nitrogen atoms. These unique metal-bridged osma-1,3-thiazine derivatives exhibit remarkable stabilities, broad spectrala bsorptions spanning the visible spectra, andc onsiderable photothermal properties, which suggests their potential applications in materialscience.Scheme1.The skeleton structures of metallapentalene (I), aza-metallapentalene (II) and metallathiazinederivatives (III).[a] J.

Reactions of Metallacyclopentadiene with Terminal Alkynes: Isolation and Characterization of Metallafulvenallene Complexes

“…As depicted in Figure , complex 2a contains an essentially planar bicyclic metallacycle framework, as indicated by the mean deviation of 0.024 Å from the least-squares plane through Os1, O1, and C1–C7. The bond lengths of Os1–C1 and Os1–C4 are 2.039 and 2.127 Å, respectively, which are close to those found in other osmacyclopentadienes . The Os1–O1 bond (2.166(5) Å) is much longer than the reported Os–O σ bond, suggesting a dative O → Os bond character.…”

Dinuclear osmium complexes as mitochondrion-targeting antitumor photothermal agentsin vivo

“…Some metalla-aromatics of Os have been first found to possess excellent photothermal conversion efficiencies (PCEs) upon 808 nm irradiation (1 W cm À2 ). [11][12][13] Recently, a series of Os-Te NPs exhibited remarkable PCEs and high potential for dual PDT/PTT (2 W cm À2 ). 14 However, no POC-based singlemolecular photothermal agent (PTA) has been reported.…”